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Jellyfish

Pacific sea nettle, eastern Pacific Ocean, tentacles up to 4.6 m (12 ft) long Jellyfish are marine invertebrates with bell-shaped bodies and stinging tentacles. Because jellyfish are not fish, scientists refer to them as scyphozoans, the "true jellyfish". They are more than 90% water and have no heart, bones or brain. Some swim by jet propulsion, but most are carried by the ocean tides and currents. Jellyfish belong to the cnidarian phylum of invertebrates, which also includes sea anemones, sea pens and coral polyps.



A school of box jellyfish

Stinging tentacles

Jellyfish float with their tentacles hanging down in the water. Each tentacle is armed with stinging cells, used to paralyse or kill prey. Jellyfish feed on small fish and other marine creatures that become caught in their tentacles. The most venomous creature on Earth is the box jellyfish. Just a touch of its powerful stinging tentacles can kill a person in four minutes.
Lion's mane jellyfish, Northern Pacific, Atlantic and Arctic oceans, bell (body) up to 2.3 m (7 ft 6 inches) wide, tentacles up...Read More >>Lion's mane jellyfish, Northern Pacific, Atlantic and Arctic oceans, bell (body) up to 2.3 m (7 ft 6 inches) wide, tentacles up to 37 m (120 ft ) long

Lion's mane jellyfish

Some jellyfish, such as the box jellyfish, have a sting powerful enough to kill a human within a few minutes of contact.

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